Solo adventurer-turned-kayaker Chris Hayward has experienced plenty on his quest to become the first person to achieve a full ascent of the Murray River.

Mr Hayward has about 700km left before his expedition finishes.

By then the 20-year-old would have paddled about 2300km upstream and then reached the summit of Mt Kosciuszko.

The journey is part of Mr Hayward’s bid to raise money for an environmental charity called Greenfleet, mixed with a desire to quench his thirst for adventure.

In the past four months, Hayward has accumulated 1714km, paddled through a month of extreme temperatures, was struck down with mercury poisoning from copious amounts of tinned tuna and come across some furry (and not so furry) friends along the way.

Why does he do it?

‘‘It’s something different,’’ he said.

‘‘I get to see the country, see the world and meet a whole range of cool people.

‘‘I’ve witnessed some incredible stuff. I’ve rescued some animals. I’ve pulled a kangaroo and a sheep from the mud.

‘‘I had an Eastern Brown Snake sitting with me on the kayak for two days, that I rescued from a houseboat.

‘‘Cockatoos I’ve had on the kayak with me. One of them was with me for four days until I got him to rescue.

‘‘I had to stop for two weeks in Tooleybuc (near Swan Hill) with a bout of gastro and food poisoning. I’d eaten so much tuna that I simply reached a point where my body couldn’t cope.

‘‘The doctors tried to put an end to the trip but I couldn’t stop just like that.

‘‘It’s definitely been an incredible experience and one that I wouldn’t get if I was travelling by bitumen in a caravan.’’

Hayward has raised about $1000 in online donations but has ‘‘no idea’’ how much is in his money tin, which proudly sits at the bow of his kayak.

The adventurer, who became the youngest person to kayak the entire length of the Murray downstream in 2012, expects to finish the journey in May.

People can donate on Mr Hayward’s website,or through his Facebook page.